Teensy 3 is not recognized by Windows after bootup until unplugged/plugged in again?

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astroyam

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Hi,

I have a Teensy 3 running a simple serial write code and LED blink code. See attached.
When I first turn on the PC with the T3 plugged in, I see the light blinking but no serial data makes it to a serial monitor opened in the TeensyDuino environment.

Then I unplug the T3 and plug it back in, and the serial monitor starts updating. So somehow Windows requires the T3 to be plugged in after power up. Is there anyway around this?

Thanks for any info.

Chris

Also: using the raw_hid teensy code and supporting PC side code, what I see is that the hid code on the PC does see and connect to the Teensy 3, but only gets zeros, until I unplug/plug back in the Teensy.
 

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  • ADC_Ser_LED.ino
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I have a Teensy3 connected to Windows 7 SP1 (64 bit) and I am able to reproduce this problem.

At this point, I don't know what's wrong, if it's on the Teensy side (something I can fix) or a driver problem in Windows (that only Microsoft can fix). I'm going to set up the protocol analyzer with a Linux machine to watch what's actually happening.

Rebooting Windows 7 several times today really makes me appreciate how nice and fast Mac and Linux boot up...
 
Fixed, not forgotten!

The last message (#8) on that thread reported the problem was solved by bug fix published in version 1.15.

But it seems to be unrelated.

Edit: I've got the protocol analyzer hooked up now, starting to dig into this one....
 
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Still working on this... it's looking like some sort of bug managing the USB buffers. I'm getting closer, but this is a pretty tough bug.
 
Good news, I think I found it. Still testing here with a heavily hacked up copy of the USB code. I believe I'll have a fix for this sometime tomorrow.
 
Here is a fix. This goes into hardware/teensy/cores/teensy3.

Please let me know if this fixes the problem for you?
 

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Has anyone (other than me) tried this yet?

I'm getting ready to make a first release candidate for Teensyduino 1.17, including this fix and lots of other stuff....
 
Hi Paul,

Yep, tested it just now and it worked A-ok. Sweet!
So as i understand this: this is a change that alters the code that goes onto the Teensy right? (as opposed to a change on the PC side).
So any code I compile with the new usb_dev.c will now be recognized after Windows boot?

Thanks mucho for the fix!

-Chris
 
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